FAQ

go-micro service interactions
How to download all dependencies after cloning the repo?

# by default this will download all modules in go.mod
go mod download
# with golang 1.14, some modules are not compatible yet. please use this as temp solution.
go env -w GOPROXY=direct
go env -w GOSUMDB=off
go mod download
# If you are importing internal/private modules, use following setting with `go mod download`
GOPRIVATE=bitbucket.com/banzaicloud/*
go mod download

How to use go modules from a Fork and branch

To use a fork, e.g., https://github.com/drnic/fatih-color, and a branch silly-changes, You need to update go.mod to use the replace helper:

module github.com/starkandwayne/my-go-project

go 1.14

require (
  github.com/fatih/color v1.7.0 // indirect
  github.com/mattn/go-colorable v0.1.2 // indirect
)

replace github.com/fatih/color => github.com/drnic/fatih-color silly-change

How to update 3rd party dependencies?

go get -u # to use the latest minor or patch releases
go get -u=patch # to use the latest patch releases
go mod tidy
# to find out why you have specific dependency
go mod why -m github.com/DATA-DOG/go-sqlmock
# if you want to get binaries into $GOHOME/bin or $GOBIN
GO111MODULE=off go get whatever
# list modules
go list -m all

How to get commitizen and cz-conventional-changelog work for non-node-git-repo?
You can get commitizen and cz-conventional-changelog work for non-node-git-repo with global installation. Here are the steps that I have followed.
```
yarn global add commitizen cz-conventional-changelog
echo '{ "path": "cz-conventional-changelog" }' > ~/.czrc; # create .czrc
cd non-node-git-repo
touch foo
git cz -a
```

How to clean cached go modules?

rm go.sum
go clean -modcache
go mod download
# this empties $GOPATH/pkg/mod/
go clean -cache -modcache

How to Prepare for a Release?
```
go mod tidy
go test all
```
how to debug in VS Code?
every time, make sure file with main() is opened before proceeding to next steps
1. open GoLang file with main() method you want to debug.
2. click on debug icon in Action Bar
3. click on Launch [▶] button.
4. Optionally edit .vscode/launch.json and add args, env etc.
How to implement integration tests?

Integration tests are e2e tests that invoke Handler methods directly and ignore networking completely. True e2e tests are Black-box tests that invoke network endpoint.

  func TestEmailService_Welcome(t *testing.T) {
    t.Parallel()
    //...
  }

  func TestEmailService_Welcome_Invalid(t *testing.T) {
      t.Parallel()
      //...
  }

  func TestEmailService_Welcome_Integration(t *testing.T) {
      if testing.Short() {
          t.Skip("skipping integration test")
      }
      //...
  }

  func TestEmailService_Welcome_E2E(t *testing.T) {
      if testing.Short() {
          t.Skip("skipping e2e test")
      }
      //...
  }

Notice the last test has the convention of:

using Integration in the test name.
checking if running under -short flag directive.

Basically, the spec goes:

"write all tests normally. if it is a long-running tests, or an integration test, follow this naming convention and check for -short"

When we want to run our unit tests, we would use the -short flag, and omit it for running our integration tests or long running tests.

Use t.Errorf t.Logf for logging. don't use logrus or default log

# Run only Unit tests:
go test -v -short
go test -v -short ./service/emailer/service
# Run only Integration Tests: Useful for smoke testing canaries in production.
go test -v -run Integration
go test -v -run Integration ./service/emailer/service

How to ssh and debug a scratch container?
Ephemeral containers are a great way to debug running pods, as you can’t add regular containers to a pod after creation. These containers executes within the namespace of an existing pod and has access to the file systems of its individual containers.
```
kubectl debug -c debug-shell --image=busybox target-pod -- sh
```
How to debug a pod that is crashing during initialization? If you pod crashing you cannot SSH to it, e.g., to see file system etc. Assuming your container has busybox at /bin/busybox, add following command to your deployment yaml.
```
# Just spin & wait forever
command:
  [
    "/bin/busybox",
    "sh",
    "-ec",
    "while :; do echo '.'; /bin/busybox sleep 5 ; done",
  ]
```
Then run kubectl exec -it $POD_NAME -- /bin/busybox sh to SSH to the container.
```
/bin/busybox ls config
/bin/busybox more config/config.yaml
```
Why some ORM model fields are pointers?
all fields having a zero value, like 0, '', false or other zero values, won’t be saved into the database but will use its default value. If you want to avoid this, consider using a pointer type or scanner/valuer, e.g:
```
// Use pointer value
type User struct {
gorm.Model
Name string
Age  *int `gorm:"default:18"`
}

// Use scanner/valuer
type User struct {
gorm.Model
Name string
Age  sql.NullInt64 `gorm:"default:18"`
}
```
Note: google wrapper types google.protobuf.StringValue, .BoolValue, .UInt32Value, .FloatValue, etc. map to pointers of the internal type at the ORM level, e.g. string, bool, uint32, float
How to run go-micro gRPC services and Micro REST Gateway on k8s?
So you want to use k8s internal CoreDNS as service registry?, then you have to follow some rules:
- Service name cannot have .(dot) due to k8s DNS limits, so make it simple via environment variables e.g., MICRO_SERVER_NAME=account
- custom build REST Gateway as micro/micro:latest image is outdated. optionally add CORS plugin.
performance If you’re concerned about performance, try
```
--selector=cache # enables in memory caching of discovered nodes
--client_pool_size=10 # enables the client side connection pool
```
You can now enable profiling in go-micro by setting MICRO_DEBUG_PROFILE=true This will enable pprof and write a cpu profile and heap profile to /tmp the profiles will be [service name].{cpu, mem}.pprof

How to rollback a git commit?

# Undoing the Last Commit:
git reset --soft HEAD~1
# If you don't want to keep these changes, simply use the --hard flag.
git reset --hard HEAD~1

# Delete Tag local
git tag --delete v0.2.6
# Delete Tag remote
git push --delete origin v0.2.6

How to Push Git Tags with Commit? Refer: how-to-push-git-tags-with-commit
```
git config --global push.followTags true
```

How to debug etcd?

kubectl port-forward service/etcd-cluster-client -n default  2379
# then
ETCDCTL_API=3 etcdctl version
ETCDCTL_API=3 etcdctl -w table member list
ETCDCTL_API=3 etcdctl get --from-key ''

Refer

PreviousChange Log

Last updated 5 years ago

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